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Diabetes Researchers Say Pig Islet Transplants May
Lead to More Cures
U of M scientists
hope to solve shortage of islet supply to cure type 1 diabetes
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"Islet transplantation
has emerged as the most promising option for restoring normal
blood sugar in people with juvenile (type 1) diabetes."
-
Juvenile Diabetes Research Foundation International.
"While research has
focused primarily on islet transplantation for type 1 diabetes,
this treatment may eventually be considered as a viable option
for all diabetic patients, both type 1 and type 2."
–
FDA
"Clinical islet
replacement therapy eventually will be widespread. Diabetes will
be conquered." Editorial, Jay S.
Skyler, University of Miami School of Medicine,
Diabetes Monitor |
|
Feb. 19, 2006 – Hope for a cure for diabetes –
which strikes about 20 percent of senior citizens – is growing daily
with new successes in research, particularly involving islet
transplants. Today, researchers announced they have been successful in
using pig islet transplants to reverse diabetes in monkeys. Islet
transplantation is viewed by many as the eventual cure for diabetes but
it has been limited to the use of human islet cells. These human cells
are of limited supply and the possibility of using pig islet cells could
vastly accelerate this cure.
Researchers have had success reversing type 1
diabetes in humans through islet transplantation:
taken from a donor's
pancreas, and transferred to a person with the disease. However, the demand
for islet cells grossly outweighs the supply. In order to make islet
transplantation a viable solution for the tens of thousands of people
with difficult-to-manage diabetes, a safe and reliable source of islet
cells must be found.
(See islet replacement background
below story.)
Researchers at the University of Minnesota's
Diabetes Institute for Immunology and Transplantation, who reversed
diabetes in monkeys using transplanted islet cells from pigs, say
survival of pig islet transplants was made possible with a novel
immunosuppressive protocol.
Graft survival did not require genetic modification
of donor pigs or coating or encapsulation of donor islets.
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Related News |
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Key Pancreatic Stem Cells Found
Feb. 19, 2006 - It as also announced today
that researchers collaborating at the Burnham Institute for
Medical Research and the Rebecca and John Moores Cancer Center
at the University of California at San Diego have shown that
endocrine progenitor stem cells exist in the adult human
pancreas, and they have demonstrated that these stem cells can
be transformed into insulin-producing cells. These findings, to
be published in the March 1 edition of Nature Medicine, advance
a major, long-range goal in developing new therapies for the
treatment of diabetes, based on transplantation of
insulin-producing cells and suggest a new approach to treating
diabetes by transforming adult progenitor cells residing within
the pancreas into insulin-producing cells.
Both type 1 and type 2 diabetes are
characterized by the loss and dysfunction of insulin-producing
cells, also known as beta cells. Beta cells reside in the
pancreatic islets, which comprise less than 2% of the pancreas.
Although the success rate for islet transplantation has
improved, it remains an experimental treatment for diabetes, due
to the shortage of islet cells and other complications. The
development of beta cell transplantation therapies is the focus
of intensive study among medical scientists working on diabetes. |
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"These results suggest it is feasible to use pig
islet cells as a path to a far-reaching cure for diabetes," said
Bernhard J. Hering, M.D., associate professor of surgery and lead
investigator.
"Now that we have identified critical pathways
involved in immune recognition and rejection of pig islet transplants,
we can begin working on better and safer immunosuppressant therapies
with the eventual goal of bringing the treatment to people."
This unprecedented progress on islet
xenotransplantation (animal-to-human) will be released today in the
medical journal, Nature Medicine.
If research continues to be successful, Hering
believes it may be possible to start clinical trials in humans in the
next three years.
To begin working toward the goal of using this
technology to help people, Spring Point Project, a non-profit
corporation, has taken concrete steps to build and operate biosecure
barrier facilities to raise high-health pigs for planned pig islet
transplant trials in humans.
Since it will take time to build biosecure
facilities that meet the federal requirements for using animal tissues
in humans, the Spring Point Project will proceed on a parallel track
with the research at the University. The goal is to have suitable donor
pigs available by the time the University has refined the
immunosuppressive treatment to a point that makes it safe for clinical
trials to begin.
Islet transplants seek to address an unmet medical
need in people with type 1 and possibly type 2 diabetes, who suffer
frequent acute and severe chronic complications.
The process is performed by isolating islet cells
from a donor pancreas and transplanting them into the portal vein of the
liver in people with diabetes. If successful, transplanted islets will
sense blood glucose levels on a minute-to-minute basis and release the
appropriate amount of insulin to achieve tight blood glucose control.
Insulin injections are no longer needed in recipients of successful
transplants.
Transplantation also offers hope in reducing the
risk of developing debilitating secondary complications of diabetes,
such as damage to the heart and blood vessels, eyes, nerves, and
kidneys.
The Medicare
Prescription Drug, Improvement, and Modernization Act of 2003 called for
the creation of a clinical trial of pancreatic islet transplantation run
by the National Institutes of Health.
Islet Replacement: Background
By Juvenile Diabetes Research Foundation –
click to link
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What is islet transplantation?
A normal pancreas contains clusters of cells known as islets, accounting
for about two percent of the mass of the pancreas's tissue.
Beta cells — one of the five types of cells in
islets — produce the insulin needed for proper metabolism. In type 1
(juvenile) diabetes, the body's immune system attacks and destroys the
beta cells.
The only way to cure diabetes for people who
already have the disease is to replace the destroyed beta cells or
replace their function. Whole-pancreas transplants have been successful
for many years, restoring insulin production in people with advanced
diabetes, but because of significant risks the procedure has been
limited primarily to recipients who are also undergoing kidney
transplantation.
Since the 1970's, researchers have pursued the goal
of islet transplantation — transplanting into people with type 1
diabetes only the islet cells that contain the needed insulin-producing
beta cells. For decades, success rates — measured by sustained
restoration of normal blood sugar control without the need for exogenous
(external) insulin — remained under ten percent until 2000, when the
demonstrated success of the Edmonton Protocol became a milestone in
islet transplantation, engendering new hope for millions.
Compared to whole-pancreas transplantation, islet
transplantation is a simpler and less invasive procedure. Healthy islets
are isolated from a donor pancreas, purified, and then infused through a
catheter (small tube) into the portal vein of the liver. Islet
transplantation can be performed as an outpatient procedure. Following
the transplant, patients take immunosuppressive drugs to keep their
bodies from rejecting the new islets and to block recurrence of
diabetes.
When successful, islet transplants can restore
normal blood sugar without the need for insulin injections and
significantly improve recipients' quality of life, making them "normal"
again, even after decades of struggles with type 1 diabetes.
Who is eligible for islet tranplantation?
Because islet transplants are experimental, they are available only to
people who fit specific defined criteria demanded by the study protocol.
To date, only adults with severely unmanageable blood glucose levels or
hypoglycemic unawareness have been eligible.
Juvenile Diabetes Foundation International Research
Centers
JDRF Islet Transplantation Centers worldwide
conduct critical innovative research in islet transplantation.
JDRF Center on Immunological Tolerance in Type-1 Diabetes at Harvard
Medical School
The primary goals of the JDRF Center on Immunological Tolerance at
Harvard Medical School will be: 1) To understand how immunological
tolerance breaks down to provoke Type-1 diabetes; 2) To learn how to
re-establish tolerance in order to prevent or cure Type-1 diabetes, in
particular via islet transplantation. In addition, it is anticipated
that the Center will add significant value to the community of Type-1
diabetes researchers by: 3) Providing a framework for integrating basic
research and clinical endeavors focused on diabetes and islet
transplantation, at Harvard Medical School and its affiliated hospitals,
and in the Boston area more generally; 4) Becoming a source for new
technologies and resources to service the world-wide community of Type-1
diabetes researchers.
JDRF Development Center for Immune Tolerance at the University of
Alabama at Birmingham
The JDRF Development Center for Immune Tolerance at the University of
Alabama at Birmingham (UAB), funded by a $1.5 million grant over three
years,will study immune tolerance related to pancreatic islet cell
transplantation.
JDRF Center for Islet Transplantation at the University of Miami
This new center, funded with a $6.75 million JDRF Center Grant, will
follow a research accelerator concept, and seek to fast-track studies
aimed at developing new therapeutic strategies that will eventually lead
to a cure.
JDRF-Danielle DeNight Center for Islet Transplantation
This center, funded by a three-year, $2.9 million grant and directed by
Kenneth Polonsky, MD, is looking to achieve three main goals. The first
is to explore methods of adapting the Edmonton protocol for islet cell
transplantation so that only a single pancreas is used. The second is to
develop and apply new methods of evaluating the function of islets in
transplant recipients. The third is to understand the effects of the
immunosuppressive drug rapamycin.
JDRF Center for Clinical Islet Transplantation at the University of
Alberta
The "Edmonton Protocol" for islet transplantation, developed at this
site in 2000, represents a true breakthrough in the treatment of type 1
diabetes, enabling patients who meet the trial's inclusion criteria to
maintain normal blood sugar levels without insulin injections. In
November 2001, JDRF launched this center with a five-year, $22.3 million
grant, so that the center's director, Dr. James Shapiro and colleagues
could focus on making the Edmonton Protocol safer, more efficient, and
accessible to people with diabetes.
JDRF Center for Islet Transplantation at Harvard Medical School
The first JDRF Center to be launched (in 1998), the Harvard Center set
out to achieve successful islet replacement therapy to cure patients
with type 1 diabetes—without a requirement for long-term
immunosuppression.
JDRF Center for Islet Transplantation at University of California, San
Francisco/University of Minnesota
Launched in 1999, the Center is pursuing ways to improve islet
transplantation success both by inducing tolerance in the recipient and
by refining the islet isolation methods to ensure high—quality islets
and reduce the number of donor material necessary for a successful
transplant.
JDRF-W.W. Smith Charitable Trust Center for Islet Transplantation at the
University of Pennsylvania
There is a great need to assess how well transplanted islets perform
their critical functions of producing insulin and maintaining normal
blood sugar levels. For meaningful progress, clinicians everywhere must
monitor and define islet function and other biological/medical results
in the same way. To create these assessment protocols, uniform
“biomarkers” and “surrogate endpoints” need to be established worldwide.
The JDRF-W.W. Smith Charitable Trust Center for Islet Transplantation at
the University of Pennsylvania is focused on islets - their isolation,
preparation, functional evaluation, and imaging in the context of
ongoing clinical trials. As an important first step, this center will
employ Positron Emission Tomography (PET) to image islets, enabling
researchers to monitor islet function and examine other immune and
metabolic markers after transplantation.
JDRF Center for Beta Cell Therapy in Europe
This center, launched in early 2002 and funded by a five-year, $10.5
million grant, aims to restore and protect beta cell mass without
requiring continuous, generalized immune suppression. The center, under
the direction of Daniel Pipeleers, M.D., Ph.D., involves a consortium of
clinical and research organizations from seven countries—Belgium,
France, the Netherlands, Denmark, Germany, the United Kingdom and
Israel. The program will develop ways to restore and protect
insulin-producing beta cells in patients with diabetes.
JDRF Center for Islet Cell Transplantation at Emory University
This Center, launched in March 2002 and funded with a $4.1 million grant
over a three-year period, addresses a critical issue facing islet
transplantation: rejection of donor islets by the patients immune
system. Wide-scale application of islet transplantation using
conventional immunosuppressants is not feasible because of long-term
side effects. The Emory researchers are investigating the use of less
toxic drugs than current therapies and also testing whether donor islets
transplanted from animals can be protected in a sheath-like membrane
from the body's immune response.
More Information Links:
Islet Cell
Resource Centers - National Center for Research Resources
Medicare.gov Information on Diabetes Screening, Supplies, and
Self-Management Training
Medicare Health Support Program
CDC- Topic: Diabetes
CDC: Diabetes and Me
NIH National Institute of Diabetes, Digestive and Kidney Diseases
NIH National Diabetes Education: You Have the Power….
Control Your Diabetes For Life
National Institute of Health- National Diabetes Information
Clearinghouse
American Diabetes Association
American Diabetes Association- All About Diabetes
American Podiatric Medical Association- Diabetes Foot Health
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